1. Field of the Invention
The present invention relates to an organic light emitting diode display and a method for driving the same.
2. Discussion of the Related Art
In accordance with development of information-oriented society, various types of demands for a display device displaying an image are growing. Accordingly, recently, various flat panel displays such as a liquid crystal display (LCD), a plasma display panel (PDP), and an organic light emitting diode (OLED) display have been used. Among the flat panel displays, the organic light emitting diode display is characterized in that driving is feasible at low voltages, a thickness is small, a viewing angle is excellent, and a response speed is high. Among the organic light emitting diode displays, an active matrix type organic light emitting diode display where a plurality of pixels are positioned in a matrix form to display the image is extensively used.
The active matrix type organic light emitting diode display is provided with a display panel including a plurality of pixels disposed in a matrix form. Each pixel includes a scan TFT (thin film transistor) responding to a gate signal of a gate line to supply a data voltage of a data line, and a driving TFT adjusting an amount of a current supplied to an organic light emitting diode (OLED) according to the data voltage supplied to a gate electrode. As a grayscale to be displayed by a pixel is increased, the current flowing through the organic light emitting diode of the pixel is increased.
Meanwhile, as an average picture level full of the image displayed by the organic light emitting diode display is increased, the number of pixels displaying a white grayscale is increased. The white grayscale means 192 to 255 grayscales where most significant two bits have a value of “11” when input digital video data are 8 bits. The current flowing through the organic light emitting diode of the pixel displaying the white grayscale is larger than the current flowing through the organic light emitting diode of the pixel displaying a gray grayscale and a black grayscale. Accordingly, as the number of pixels displaying the white grayscale is increased, power consumption of the organic light emitting diode display is increased. Therefore, currently, there is a demand for a way to reduce power consumption of the organic light emitting diode display.